Senior UX Researcher- Mercari Marketplace (Commerce New Service)

Description

Employment Status: Full-time
Work Hours: Full Flextime (no core time)
Office: Roppongi, Minato City, Tokyo, Japan (Hybrid)

The New Business Design Team leads end-to-end user experience design for emerging product initiatives at Mercari, shaping intuitive, trustworthy, and high-quality experiences for domestic and international users. We partner closely with Product, Engineering, Research, and Business Development to explore new problem spaces and raise the bar for craft, consistency, and innovation.

The New Business organization at Mercari is focused on identifying and scaling transformative opportunities that expand Mercari's market reach and unlock new revenue streams. We pursue zero-to-one initiatives and strategic bets across emerging commerce models, user segments, and geographic markets—from expansion into new verticals to testing innovative transaction types. Our team operates at the intersection of exploration and execution, moving quickly to validate concepts while maintaining rigor in decision-making.

We are seeking an experienced User Researcher to join the New Business UX research function at Mercari. This role requires full-stack research capability—the ability to move fluidly between lightweight tactical research (rapid testing, feedback collection, quick iterations) and deeper strategic research (market exploration, business model validation, strategic recommendations), while also leading research initiatives independently and partnering cross-functionally with product, design, and business teams.

You will own research strategy for assigned new business initiatives, ranging from early-stage market exploration to validation of emerging concepts. You'll design and execute a mix of qualitative and quantitative research methods—from quick concept tests and user feedback loops to in-depth ethnographic fieldwork and large-scale validation studies—and synthesize findings into clear, actionable recommendations that directly influence business direction and product decisions. You're equally comfortable running a one-week validation sprint as you are designing and leading a multi-month strategic research initiative.

As the research voice in an exploratory, fast-moving environment, you'll need to balance rigor with speed: designing research that generates confidence in decision-making while moving quickly enough to support iterative business hypothesis testing. You'll also play a key role in building research operations and practices for the new business org, helping establish scalable processes, repositories, and frameworks that mature as we grow and that can be shared across Mercari.

This role is ideal for a researcher who thrives working with ambiguity, who has demonstrated success leading research independently (not just executing), who brings international and cross-cultural perspective, and who is excited by the challenge of validating entirely new business models and market opportunities.

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Work Responsibilities

Strategic Research Leadership

• Lead end-to-end research initiatives for new business concepts, including framing research questions, designing methodology, managing timelines, and communicating findings to senior leadership and stakeholders.
• Conduct international and cross-cultural user research, including planning and executing fieldwork in key markets (e.g., US, Asia-Pacific regions) to understand local user behaviors, market dynamics, and competitive landscapes.
• Partner with product, business development, and design leads to translate business hypotheses into rigorous research frameworks that test viability and reduce risk.
• Make methodological choices that balance research rigor with business velocity—knowing when to run quick validation tests vs. deeper exploratory studies.
• Synthesize research findings into strategic recommendations and business insights that inform go/no-go decisions, product strategy, and market entry decisions.

Research Operations & Infrastructure

• Establish and evolve research ops best practices for the new business organization, including participant recruitment strategies, repository management, and insight communication frameworks.
• Build and maintain research repositories, market databases, and competitive intelligence systems that enable ongoing learning across new business initiatives.
• Support research at scale by leveraging AI tools thoughtfully across the research workflow—from study planning and participant recruitment to analysis, synthesis, insight visualization, and reporting.
• Help establish shared research artifacts (playbooks, templates, frameworks) that enable rapid research execution and knowledge sharing across the new business team.

Cross-functional Collaboration & Stakeholder Management

• Partner with PMs, designers, marketing and business development stakeholders to identify research needs early and embed research into decision-making cycles.
• Communicate research findings effectively to diverse audiences—executives, product teams, and design partners—adapting communication style and rigor to stakeholder needs.
• Build trust and credibility with stakeholders through transparent research practices, clear methodology communication, and a track record of actionable insights.
• Mentor and support junior researchers or contractors as the team grows.

Continuous Learning & Innovation

• Stay current with research trends, methodologies, and tools—particularly in international research, business model validation, and emerging commerce spaces.
• Explore and advocate for thoughtful applications of AI in the research function, helping Mercari develop a more efficient, innovative research practice.
• Contribute to the broader UX research community at Mercari, sharing frameworks and learnings across teams.

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Unique Challenges (Looking for someone who is…)

• Full-stack and versatile: Comfortable moving between modes—able to run quick, lightweight validation tests one week and design a rigorous multi-month strategic research initiative the next. You don't mind getting hands-on with execution, but you're also capable of stepping back to think strategically about research direction.
• Strategically minded: Able to frame research questions that directly address business risk and opportunity. You understand how research fits into augments business decision-making, not just design iteration.
• Intellectually rigorous: Comfortable defending methodology choices, challenging assumptions (yours and others'), and insisting on evidence-based thinking—even under time pressure.
• Operationally savvy: Excited to build research infrastructure and processes—not just execute individual studies, but help create scalability and organizational capability as the team grows.
• Internationally experienced: Genuinely curious about cultural differences, local markets, and cross-cultural user research. Ideally with hands-on experience conducting international field research, ethnographic studies, or in-person research across multiple countries.
• Adaptable and entrepreneurial: Thrives in ambiguous, fast-paced environments. Comfortable with incomplete information, shifting priorities, and the inherent uncertainty of new business exploration. You move fast without sacrificing rigor.
• Communicative and collaborative: Strong storyteller who can make research findings memorable, accessible, and actionable. Enjoys building relationships across functions and translating research into business language.
• Comfortable with AI tools: Proactive about exploring and applying AI to improve research speed, quality, and scale—while maintaining research rigor and ethical practices.
• Learning-oriented: Brings curiosity about the ecommerce space, new business models, and what drives user adoption in emerging categories.

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Qualifications

Required Experience/Skills

• 5+ years of UX research experience in-house, agency, consulting, or hybrid roles, with demonstrated ability to lead research independently (not just execute studies).
• Proven experience conducting strategic research that has directly informed business decisions or product strategy—you can articulate 2-3 examples where your research shaped direction.
• Strong methodological expertise across qualitative and quantitative methods: user interviews, ethnographic research, usability testing, surveys, analytics, concept validation, and A/B testing.
• International field research experience: Hands-on experience planning and conducting research across multiple countries/cultures, including in-person fieldwork, ethnographic research, or international market studies. Bonus: US market research specifically.
• Research operations and/or strategy experience: Familiarity with research repository management, research planning frameworks, VOC programs, or scaling research across teams.
• Excellent communication skills in English (verbal and written) at a professional/executive level—you can distill complex findings into clear narratives for senior leaders.
• Competence with AI tools and research technology: Experience using AI for research workflows (synthesis, insight generation, etc.) and familiarity with research tools (UserTesting, Maze, Qualtrics, survey platforms, or equivalent).
• Stakeholder management: Experience presenting to and influencing senior stakeholders, translating research into business language, and building buy-in for research-informed decisions.

Preferred Experience/Skills

• Experience with new market exploration or business model validation: You've conducted research that tested the viability of new product categories, market entry decisions, or emerging transaction types.
• Ecommerce and/or marketplace domain expertise: You understand ecommerce user behaviors, conversion funnel dynamics, trust/safety considerations, and/or marketplace dynamics.
• Japanese language skills (spoken and written)—particularly helpful for stakeholder communication and research moderation, but not required.
• Mandarin or Cantonese language skills: A bonus for conducting research in Asia-Pacific markets.
• Experience with emerging product categories (e.g., anime, comics, gaming, entertainment, creator economy, Web3/blockchain, etc.): Familiarity with niche communities or vertical markets.
• Experience working in fast-moving startups or scale-ups: Comfort with ambiguity, wearing multiple hats, and moving quickly without perfect information.
• Familiarity with quantitative analysis tools (R, Python, Tableau, Looker, or equivalent): Not required, but valuable for analyzing large research datasets independently.

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Language Requirements

• English: Required - C1 (Proficient User - Professional working proficiency and above)
• Japanese: Beneficial
• Mandarin/Cantonese: Beneficial

For details about CEFR, see here.